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The Single UNIX &reg; Specification, Version 2<br>
Copyright &copy; 1997 The Open Group

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<h4><a name = "tag_000_002_065">&nbsp;</a>NAME</h4><blockquote>
ctime, ctime_r - convert a time value to date and time string
</blockquote><h4><a name = "tag_000_002_066">&nbsp;</a>SYNOPSIS</h4><blockquote>
<pre><code>

#include &lt;<a href="time.h.html">time.h</a>&gt;

char *ctime(const time_t *<i>clock</i>);
char *ctime_r(const time_t *<i>clock</i>, char *<i>buf</i>);
</code>
</pre>
</blockquote><h4><a name = "tag_000_002_067">&nbsp;</a>DESCRIPTION</h4><blockquote>
The
<i>ctime()</i>
function converts the time pointed to by
<i>clock</i>,
representing time in seconds since the Epoch, to local time in the form
of a string.
It is equivalent to:
<pre>
<code>
asctime(localtime(clock))
</code>
</pre>
<p>
The
<i><a href="asctime.html">asctime()</a></i>,
<i>ctime()</i>,
<i><a href="gmtime.html">gmtime()</a></i>
and
<i><a href="localtime.html">localtime()</a></i>
functions return values in one of two static objects: a
broken-down time structure and an array of
<b>char</b>.
Execution of any of the functions may overwrite the information
returned in either of these objects by any of the other
functions.
<p>
The
<i>ctime()</i>
interface need not be reentrant.
<p>
The
<i>ctime_r()</i>
function converts the calendar time pointed to by
<i>clock</i>
to local time in exactly the same form as
<i>ctime()</i>
and puts the string into the array pointed to by
<i>buf</i>
(which contains at least 26 bytes)
and returns
<i>buf</i>.
<p>
Unlike
<i>ctime()</i>,
the thread-safe version
<i>ctime_r()</i>
is not required to set
<i>tzname</i>.
</blockquote><h4><a name = "tag_000_002_068">&nbsp;</a>RETURN VALUE</h4><blockquote>
The
<i>ctime()</i>
function returns the pointer returned by
<i><a href="asctime.html">asctime()</a></i>
with that broken-down time as an argument.
<p>
On successful completion,
<i>ctime_r()</i>
returns a pointer to the string pointed to by
<i>buf</i>.
When an error is encountered, a NULL pointer is returned.
</blockquote><h4><a name = "tag_000_002_069">&nbsp;</a>ERRORS</h4><blockquote>
No errors are defined.
</blockquote><h4><a name = "tag_000_002_070">&nbsp;</a>EXAMPLES</h4><blockquote>
None.
</blockquote><h4><a name = "tag_000_002_071">&nbsp;</a>APPLICATION USAGE</h4><blockquote>
Values for the broken-down time structure can be obtained by calling
<i><a href="gmtime.html">gmtime()</a></i>
or
<i><a href="localtime.html">localtime()</a></i>.
This interface is included for compatibility with older
implementations, and does not support localised date and time
formats.
Applications should use the
<i><a href="strftime.html">strftime()</a></i>
interface to achieve maximum portability.
</blockquote><h4><a name = "tag_000_002_072">&nbsp;</a>FUTURE DIRECTIONS</h4><blockquote>
None.
</blockquote><h4><a name = "tag_000_002_073">&nbsp;</a>SEE ALSO</h4><blockquote>
<i><a href="asctime.html">asctime()</a></i>,
<i><a href="clock.html">clock()</a></i>,
<i><a href="difftime.html">difftime()</a></i>,
<i><a href="gmtime.html">gmtime()</a></i>,
<i><a href="localtime.html">localtime()</a></i>,
<i><a href="mktime.html">mktime()</a></i>,
<i><a href="strftime.html">strftime()</a></i>,
<i><a href="strptime.html">strptime()</a></i>,
<i><a href="time.html">time()</a></i>,
<i><a href="utime.html">utime()</a></i>,
<i><a href="time.h.html">&lt;time.h&gt;</a></i>.
</blockquote><h4>DERIVATION</h4><blockquote>
<i>ctime()</i> derived from Issue 1 of the SVID.
<P>
<i>ctime_r()</i> derived from the POSIX Threads Extension (1003.1c-1995).
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UNIX &reg; is a registered Trademark of The Open Group.<br>
Copyright &copy; 1997 The Open Group
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